Marihuana has been known to people for hundreds of years. Today, marihuana is either legal or decriminalized in many countries, particularly in Europe and the Americas, which may encourage use of the drug. Cannabis and its derivatives are used in medicine on the recommendation of doctors, including for the treatment of multiple sclerosis or drug-resistant epilepsy. There is a group of people who turn to marihuana on the street without regard to contraindications and side effects, and these are the recreational users who struggle with problematic use or addiction . Buying marihuana outside of the medical market means that the user may not realize the negative health effects of their use, and there are serious risks associated with the negative effects of the natural substances found in marihuana or the numerous and common marihuana contaminants, such as mercury and pesticides, among others. This review justifies the prescription of pharmaceutical-grade medical marihuana as part of health harm reduction for a group of cannabis use disorder patients who are unlikely to stop using marihuana from untested or illicit sources, while also discussing ethical and economic issues.